The invention relates to an open refrigerated display case and a flow stabilizing device for an open refrigerated display case.
The display of chilled or frozen items is commonplace in many retail environments, most notably in supermarkets. Conventionally, such items have been displayed in refrigerated display cases having glass doors to allow customers to browse items before opening the doors to access the items. However, the presence of such doors has been seen as problematic in that they make it difficult for several customers to access the contents of the case, as well as providing an obstruction when open, narrowing the usable aisle space.
It is therefore common for supermarkets to use open-fronted display cases (Open Refrigerated Display Cases; herein “ORDCs”). ORDCs utilize an air curtain which is cooled to below ambient temperature and propelled downward, across the open front of the display case. The air curtain separates the refrigerated interior of the display case from the ambient air surrounding the display case. The air curtain thus keeps the cool air inside the display case from spilling out due to buoyancy effects, and also provides a barrier from other external motions of air around the display case. ORDCs therefore do not need any physical barrier separating customers from the contents of the display case. Accordingly, ORDCs provide a desirable method of displaying food and other perishable goods as they allow both easy access and clear visibility of merchandise.
However, as a direct consequence of their open design, ORDCs do have significantly higher energy consumption compared to the closed-fronted alternative. The main energy losses occur within the air curtain, and are caused by the entrainment of warm ambient air into the air curtain and the turbulent mixing which occurs within the air curtain itself. The entrainment of warm ambient air causes an increase in temperature within the air curtain, and this warmer air must be cooled as it re-circulates through the system. It has been estimated that 70% to 80% of the cooling load of an ORDC is due to such effects.
In recent years, multi-decked designs have become commonplace to maximize the display space per unit of floor space. Consequently, the air curtains of such ORDCs must seal a larger display area. This has exacerbated entrainment issues and the resulting energy losses, as well as making the design of air curtains more challenging, particularly in respect of ensuring product integrity and temperature homogeneity while attempting to minimize their energy consumption.
The invention thus seeks to improve the efficiency of ORDCs by reducing entrainment within the air curtain.